With the need for reducing costs or times associated with business trips, more companies are moving towards transmission systems to have teleconference or videoconference among remotely located offices via a communication network. The transmission systems allow transmission of image data or voice data among a plurality of transmission terminals that are remotely located from one another through a communication network such as the Internet to facilitate communication among the plurality of transmission terminals.
The recent transmission systems have a function of notifying a user at a request transmission terminal of information indicating the current state of a counterpart transmission terminal before the user at the request transmission terminal starts communication with a user at the counterpart transmission terminal. For example, the transmission system described in U.S. Patent Application Publication No. 2007/0263075 manages user names and associated identities of potential users at transmission terminals such that the stored information regarding the potential users are constantly refreshed as users at transmission terminals log in or out. Before the user at the request transmission terminal initiates videoconference, the user at the request transmission terminal accesses a screen that lists user names and associated identities of potential users that are constantly refreshed. While this prevents the user at the request transmission terminal from initiating videoconference with a user who is not currently logged in, the screen that is accessed by the user is constantly refreshed as the login state of the user is changed, thus causing perception of flicker in screen.